Experimental and simulation results of Si self-diffusion and B diffusion in SiO2, formed directly on Si substrates by thermal oxidation, were presented. It was shown that both Si and B diffusion in SiO2 were enhanced by SiO generated at the Si/SiO2 interface and diffused into SiO2. It was also shown that the existence of high-concentration B in SiO2 enhanced SiO diffusion, which then enhanced both Si self-diffusion and B diffusion. This correlated diffusion of Si and B in SiO2 was consistent with first-principles calculated results, which showed that B diffused via a complex of BSiO; with frequent bond-exchanges in the SiO2 network. On the basis of the results, an enhancement of Si self-diffusion and B diffusion in SiO2 by compressive strains and their retardation by tensile strains were suggested.

Enhanced Si and B Diffusion in Semiconductor-Grade SiO2 and the Effect of Strain on Diffusion. M.Uematsu, H.Kageshima, S.Fukatsu, K.M.Itoh, K.Shiraishi, M.Otani, A.Oshiyama: Thin Solid Films, 2006, 508[1-2], 270-5